Lecture 35: Clinical Evaluation of balance Flashcards
Balance is made up of…..
Balance made up of:
- Ocular cues
- Proprioception
- Vestibular system
What does Vestibular System Do?
- Sense of position
- Gaze stabilisation
What do you do in a Clinical testing with a patient who may have impaired vestibular system?
- History
- Ear examination (e.g. cholesteatoma)
- Eye movements (e.g. nystagmus or smooth pursuit)
- Head thrust
- Fukuda (Unterberger) stepping test
- Fistula test
- (press into their ear, and they get dizzy)
- Dix Hallpike
- Laboratory
- Audiogram
- Optokinets
- Caloris
- Computerised head thrust
- vEMP
What History should you take for someone with vertigo?
- True vertigo or not (exclude after effects)
- Episodic nature (on/off, or continuous)
- Duration of vertigo (minute, hours, days)
- 1 minute = Benign paroxysmal positional vertigo (BPPV) or vestibular migrane
- Hours = meniyere’s, acoustic myoma
- Days = Vestibular neuronitis
- Precipitating factors: (what brings this on)
- Head movement
- Loud noise
- Diving/valsalva
- Migraine
- Associated factors:
- Migraines
- Tinnitus
- Hearing loss
- Aural fullness
- Stroke
Draw the flow diagram to diagnose the cause of vertigo
(real life application)
What are the 3 semi-circular canals equivalent to in real life?
This, but it doesn’t detect detect acceleration and gravity.
What detects linear acceleration?
Utricle(horizontal) and Saccule(vertical)
Little crystals are embedded into the matrix.
When you go up and down the elevator, the crystals (are heavier) so it displaces the matrix.
What are the sensory structures in the vestibular system?
- 1) Ampulla of the semicircular canals
- detects movement of fluid
- 2) Dilated end of canal
- 3) Contains sensory neuroepithelium, cupula, supporting cells
- Cupula is gelatinous mass extending across at right angle
- it extends completely across, not responsive to gravity
- Crista ampullaris is maded up of sensory hair cells and supporting cells
Each afferent neuron has a baseline firing rate
- Deflection of _______towards ______ increase in firing rate of afferent neuron
- Deflection ______causes a decrease in firing rate
Each afferent neuron has a baseline firing rate (left figure)
- Deflection of stereocilia towards kinocilium increase in firing rate of afferent neuron
- Deflection away causes a decrease in firing rate
Kinocilia are located _________
Kinocilia are located closest to utricle in lateral canals and are on canalicular side in other canals (right figure)
- Amupllopetal flow (toward the ampulla) are excitatory in lateral canals, inhibitory in superior/posterior canals
- Ampullofugal flow (away from the ampulla) has opposite effect
- _____________(toward the ampulla) are excitatory in later canals, inhibitory in superior/posterior canals
Kinocilia are located closest to utricle in lateral canals and are on canalicular side in other canals (right figure)
- Amupllopetal flow (toward the ampulla) are excitatory in later canals, inhibitory in superior/posterior canals
- __________flow (away from the ampulla) are inhibitory in later canals, excitratory in superior/posterior canals
Kinocilia are located closest to utricle in lateral canals and are on canalicular side in other canals (right figure)
- Amupllopetal flow (toward the ampulla) are excitatory in later canals, inhibitory in superior/posterior canals
- Ampullofugal flow (away from the ampulla) has opposite effect
- Amupllopetal flow (toward the ampulla) are _____________
- Ampullofugal flow (away from the ampulla)___________
- Amupllopetal flow (toward the ampulla) are excitatory in later canals, inhibitory in superior/posterior canals
- Ampullofugal flow (away from the ampulla) has opposite effect
Vestibulo-Occulular Reflex _______
the goal is to ________
VOR stabilizes images on the retina
The goal is for eye movement to be equal and opposite to the head movement
COWS (Cold Opposite, Warm the Same)
Peripheral vestibular malfunction usually means ______function (rarely hyperfunction)
Peripheral vestibular malfunction usually means reduced function (rarely hyperfunction)
If someone comes in with Vestibular Neuritis, what should you advise them to do?
Brain adjust by cerebellar clamp, which starts to ignore input from the right side and resets.
(Central compensation to establish a new equilibrium)
Never tell patient to stay in the bed, which can end up with chronic dizziness! Need to get out of the bed, which helps patient re-equilibrate by cerebellar clamp!
Describe the Head Thrust Test
- Gently grasp patient’s head, tilted down 30° (lateral semicircular canal that is 30° up is now sitting parallel).
- Instruct patient to fixate on target (your nose)
- Rapidly rotate head 15‐20° to one side, then the other (rapid enough to activate their vestibular system and not their eye)
-
Eyes should remain on target. Watch for a catch_‐_up saccade to refixate after movement is complete
- The patients will tell you (early in the disease) that when they turn their head towards the side they’ve lost their function, the world feels like it’s still catching up (e.g. get dizzy)
As we turn head to one side, eyes are going in the opposite direction to stabilise the image.
Describe the Calorics test
- Patient lying down with lateral semicircular canal orientated up
- Cold water/air (in right ear) cause endolymph to become dense and fall
- Deflection cupula away (inhibit right side) so vestibular hypofunction, which cause nystagmus fast phase to beat to the opposite side (left).
Warm Calorics
Endolymph becomes less dense, rises and causes deflection cupula towards so increased firing (excitation) of right ear, therefore n_ystagmus beat towards the stimulation._
COWS
- Cold water in one ear (hypofunction), fast phase of nystagmus is in the opposite direction.
- Warm water in one ear (hyperfunction), fast phase of nystagmus is in the same direction.
Implication of Calorics
Things that causes dizziness such as cold ear drops, suctioning (air movement), ear syringing, mastoid cavity clean (LSCC [lateral semi-circular canal] underneath the mastoid bone).
What are the implications of calorics?
Implication of Calorics
Things that causes dizziness such as cold ear drops, suctioning (air movement), ear syringing, mastoid cavity clean (LSCC [lateral semi-circular canal] underneath the mastoid bone).
Describe the Fukuda (unterberger stepping test)
Takes away their visual and proprioceptive cues (after eyes closed and head shaking), testing just their vestibular function.
- Ask them to close their eyes with their arms out front
Walking on the same position (50 steps), should turn to the side of their deficit (they will start to rotate)
Imagine plane, one side of engine fails, plane turns to the direction of failure.
Describe the Dix Hallpike Manoeuvre test
Turn head to one side 45 degrees, then held down quickly to head extension of 30 degrees while keeping the lateral head position, _check eye movements (_for ~30 secs), then turn the head to the other side
This is a diagnostic maneuver used to identify benign paroxysmal positional vertigo (BPPV)
- T_est is positive_ if the patient has vertigo and there is torsional/geotropic nystagmus (fast phase to the faulty side) (nystagmus typically have some latency that starts after a few seconds in BPPV).
- Vertigo or nystagmus typically may not appear after second or third manoeuvre.
What clinical examination is often used to diagnose BPPV?
Dix-Hallpike Manoeuvre
Turn head to one side 45 degrees, then held down quickly to head extension of 30 degrees while keeping the lateral head position, check eye movements (for ~30 secs), then turn the head to the other side
This is a diagnostic maneuver used to identify benign paroxysmal positional vertigo (BPPV)
- Test is positive if the patient has vertigo and there is torsional/geotropic nystagmus (fast phase to the faulty side) (nystagmus typically have some latency that starts after a few seconds in BPPV).
- Vertigo or nystagmus typically may not appear after second or third manoeuvre.
Describe the Epley’s Manoevre
Epley (Repositioning) Manoeuvre
Turn head to _faulty side 4_5 degrees, then held down quickly to head extension of 30 degrees while keeping the lateral head position for 1min (nystagmus may appear for a few seconds), then turn head to the other unaffected side for 1min (may get opposite nystagmus for a few seconds), then shoulder on the side and head kiss the bed for 1min (still towards unaffected side), then turn legs to the bedside, sit up maintaining 45 degree head rotation for 1min.
This is a maneuver used to treat benign paroxysmal positional vertigo (BPPV) of the posterior or anterior canals.
- It works by allowing free floating particles from the affected semicircular canal to be relocated, using gravity, back into the utricle, where they can no longer stimulate the cupula.
Describe the VEMP
VEMP (Vestibular evoked myogenic potential)
Loud noise sign travels from utricular and saccular macula to vestibular nuclei, which stimulates extraocular muscle via oculomotor nucleus, and sternocleidomastoid muscle via motoneurons.
Therefore, animal turns the head and eye to the stimulus. (e.g. when a doe you hear a loud noise, you want to see if it is a threat/lion.)
You can test this response in humans
